The power conversion efficiency of dye-sensitized solar cells can be increased above 8% by using a one-dimensional bilayer nanofiber photoanode. The smaller-diameter nanofiber layer with a large surface for adsorbed sensitized dyes efficiently harvests sunlight and transports photogenerated electrons, while the bigger-diameter nanofiber layer reflects and traps sunlight in the photoanode. Both nanofiber layers can be fabricated readily by electrospinning.